The "old" version of Gef3D was based on Java3D and had serious memory
problems. So I started a new version from scratch, this time based on
LWJGL. Also, the old version was a port of GEF, i.e. GEF was made 3D
and it was no longer compatible with the original version. The new
Gef3D version is "only" an extension of GEF adding 3D features.

Since the old version is no longer maintained (and since it is not
really useable), it is no longer available. The new version is still in
development, maybe finished in February, but it is not yet clear under
what license and conditions it will be released.